Apparatus for treating metal sheets



Sept. 12, 1939. E, I, HUFF 2,172,386

APPARATUS FOR TREATING METAL SHEETS Filed July 2'7, 1936 4 Sheets-Sheetl A Away/w? fiiiZ/a/ I E mm f Ha Sept. 1 1939. I E. I. HUFF 2,172,386

APPARATUS FOR TREATING METAL SHEETS Filed July 27, 1936 4 Sheets-Sheet 210/ Q 7/ 2 I /03 i I I I l I I I I l I I l I l I l I I I Lllllllllb @f MY [Wm/ 5/:

Sept. 12, 1939. I E. I. HUFF 2,172,386

APPARATUS FOR TREATING METAL SHEETS Filed July 27, 1936 4 Sheets-Sheet 4POWER 70 Mo role 8/ CMVEYE POWER SWITCH To M0701? 5.9

UPPER L/M/ T A REVEIPS/IVG 0PPER L/MITB m A LOWE? LIM/ TA LOWE F LIMITSH/FI'ER LIMIT SWITCH SH/FIER PM 77MB? 3 T11R75 SEQUENCE COIITRULLERssauzwce com-R04 M070)? /6/ mm: INTER VALS flaps w til Patented Sept.12, 1939 UNITED STATES 2,172,386 APPARATUS FOR. TREATING METAL sHEE'rsEdward I. Huff, Reiffton, Pa., assignorto Hufl Equipment Company,Pittsburgh, Pa., a corporation of Pennsylvania Application July 27,1936, Serial No. 92,725

- 9 Claims.

This invention is directed to apparatus for treating metal sheets, moreparticularly, to apparatus for the normalizing and annealing of metalsheets, in particular, steel sheets.

It has hitherto been the custom, in the continuous annealing ornormalizing of steel sheets, to pass the sheets continuously through afurnace in a substantially horizontalposition. This practice has manydisadvantages, among which may be mentioned the necessity for the use ofdummy sheets, the necessity for providing water-cooled shafts for therollers used, and the marking of the surface of the metal sheets beingtreated. It has been proposed, to avoid certain of the diflicultiesencountered in passing steel sheets through a furnace in a horizontalposition, to pass the steel sheets through a furnace while the sheetsare in a vertical position. However, while some of the disadvantages ofhorizontal treatment are avoided by such a procedure, seriousdifliculties in thesatisfactory treatment of the steel sheets stillremain. Thus, for example, the steel sheets are marked by the clampsused to support them as they pass through the furnace. Moreover, thefurnace construction necessary for the practice of this type ofannealing, namely, a tunnel open at both ends, inevitably causes aircurrents'which result in uneven heating of the steel sheets beingannealed. Consequently, the sheets are twisted and warped to some extentduring the annealing process, and it has not been possible to produce aflat sheet uniformly annealed.

In accordance with my invention there is provided apparatus for thecontinuous annealing of, for example, sheet steel in which a uniformtemperature is maintained throughout the furnace, and the steel sheet issupported in the furnace in a vertical position. without the use ofclamps or any other device that would mark the surface of the annealedsheet. is a consequence, it is possible to obtain an annealed sheet thatis unwarped, is uniformly annealed throughout, and is free from surfacemarkings. Moreover, by the provision of automatic control means it ispossible to insure an absolute uniformity in the annealing treatmentgiven each sheet ofsteel, while nevertheless retaining the utmostflexibility in the temperature and time factors of the annealingprocess.

In accordance with my invention, the sheets of steel or other metal tobe normalized or annealed are fed successively in position beneath theannealing furnace. Eachsheet in-succession is then automaticallyraised-up into position in the annealing furnace where it remainssuspended vertically in the furnace until the desired heat treatment hasbeen effected. The sheet is then lowered out of the furnace andautomatically conveyed away from the furnace to a point 5 of dischargeor to pickling, scrubbing vats, or the like.

The apparatus which is preferably utilized in accordance with myinvention comprises a substantially completely enclosed annealingfurnace 10 adapted to hold a single sheet'of steel or other metal to betreated suspended vertically therein and provided with, as the soleopening, a relatively narrow slot in the bottom of the furnace throughwhich the sheets of steel may enter and 15 leave the furnace; a conveyoradapted to bring the sheets of steel successively into position beneaththe furnace; hoisting means partially contained in the furnace forraising the steel sheets from the conveyor into the furnace and loweringthem again after the heat treatment is over onto the conveyor; andmeansfor loading the steel sheets onto the conveyor and removing themfrom the conveyor.

The preferred embodiment of my invention is shown in the accompanyingdrawings in which Fig, 1 is a front elevation, partly in section, of theapparatus in accordance with my invention, including the furnaceconveyor and loading and unloading means. 30

Fig. 2 is an end view showing the discharge end of. the apparatus shownin Fig. 1.

Fig. 3 is a vertical sectional view through the apparatus shown in Fig.1, looking toward the n charging end of the apparatus.

Fig. 4 is a detail view showing the upper end of a sheet of steel orother metal prepared for treatment in the apparatus shown in Fig. 1.

Fig. 5 is a detail view of the carrier bar utilized for supporting thesheets of steel during treatment.

Fig. 6 is a fragmentary, plan view of the seouene controller used inaccordance with my invention for controlling the passage of the steelsheets through the apparatus.

Fig. 7 is a. plan view showing the time control device used fordetermining the interval of time during which the sheet steel remains inthe furnace.

Fig, 8 is a diagrammatic wiring diagram showing the arrangement ofinterlocking controls used to secure proper sequence of operations andto prevent improper sequence of operations.

And Fig. 9 is a diagrammatic sketch showing the operation of thesequence control illustrated in Fig. 6.

As is best shown in Fig. 1, the apparatus in accordance with myinvention comprises a furnace, indicated generally by the referencecharacter I; a conveyor, indicated generally by the reference character3, adapted to' bring sheets of steel successively into position beneaththe furnace; a hoisting mechanism, indicated generally by the referencecharacter 5, for raising the sheets of steel into the furnace andlowering them again onto the conveyor 3; a loading mechanism, indicatedgenerally by the reference character 1, for feeding sheets of steel ontothe conveyor 3; and an unloading mechanism, indicated generally by thereference character 9, for removing treated sheets of steel from theconveyor 3 and discharging them from the apparatus.

The furnace I is' enclosed in a welded steel shell II, which issupported in conventional manner from the buck-stays I3, the bottom tiemembers I5 and the top tie members I1. Inside the steel shell II isprovided the usual heat insulating ma-. terial I9 and refractorymaterial 2 I. A plurality of electric heating units 23 fixed on theinterior wall of the heating chamber proper 25 provide the necessaryheat. It will be noted that heating chamber 25 is substantially entirelyenclosed, the

only opening therefrom being the relatively narnamed in the supportingmembers 41. Likewise.

fixed on the shaft 45, is a ratchet wheel 49, which is engaged by alever 5|, acting as a pawl. Lever 5| is held against the ratchet wheel49 by a spring 53 attached to the support 41, and is pivoted at itsopposite end to the crank disc 55, which is driven through a reductiongearing 51 by the electric motor 59. Fixed on the same shaft as thecrank disc 55 is a cam 6| adapted to actuate in its rotation controlswitch C, carried on the support 41, of the interlocking controlcircuit.

The hoisting mechanism 5 comprises a pair of drums or sprockets 1|mounted on a shaft 13 and enclosed in housings 15. The shaft 13 extendsbeyond the housing 15, across the top-of the furnace, and is driventhrough gears 11, 19 by the electric motor 8| supported on the top tiemembers I1 of the furnace. A pair of chains or cabies 93 are secured;to, and adapted to be wound on, the drums 1| and pass through openingsin the roof of the heating chamber 25. Positioned within the heatingchamber 25 andamxed to the lower ends of the chains or cables 33 is acarrier member 81 having inturned, concave flange elements 89 adapted toreceive and hold thesheet metal carrier bar 9| shown in Fig. 5, whichwillbe hereinafter described.

Secured to one of the chains or cables are a pair of sleeve members 93carrying a projection adapted to actuate the interlocking control switchE of the interlockingcontrol circuit. Sleeves 93 are capable of beingadjusted along the chain or cable 83 so that one of them wil. trip oractuate the switch arm of switch E downwardly when the carrier 81 is inits lowermost position with the carrier bar 9| resting on the,conveyor3, while the other sleeve 93 will trip the switch arm 95 upwardly whenthe carrier 81 is in its uppermost position adjacent the roof of theheating chamber 25.

The loading mechanism 1 and the unloading mechanism 9 are similar inconstruction and comprise cars IIII adapted to travel along the railsI93 positioned along the top of the. furnace I. Each car IIII carries anelectric motor I95 anda drum I91 driven thereby. A pair of cables I09are secured to and adapted to be wound on each of the drums I01. Thesecables pass from the drums I01 over pulleys III and are-fastened attheir lower ends to the carrier II3. This carrier runs on rollers II5within the track formed by channel members 1. Channel members I" aresupported at their ifpper ends from the cars IIII and are free at theirlower ends. The carrier I I3 is provided with apair of inturned concaveflanges I I9, similar to those of the carrier 61, and adapted, likethose of the carrier 31, to receive and support the carrier bars 9I.'

On one of the channel members 1- of the loading mechanism 1 there isprovided a pair of interlocking control switches A and A. These switchesare adapted to be tripped or actuated by the rollers N5 of the carrierII3. Switch A, positioned at the upper end of thechannel member.

H1, is adapted to be actuated by the carrier 3 when it is in itsuppermost position, while switch A, positioned at the lowerend ofchannel member I |1,is adapted to be actuated when the carrier I I3 'isin its lowermost position. A similar pair of interlocking switches B andB are provided on one of the channel members II1 of the unloadingmechanism 9.

Each of the cars IIII is pivotally connected to a pair of links I2 I,which in turn are pivotally connected, at their other ends, to a pair ofcrank discs- I23. The crank discs I23 are fixed on a shaft I25, which isjournaled in the frame member I21 supported on the top tie members I1 ofthe furnace I.

Shaft I25 is driven through gears I29, I3| by elec-,

tric motor I 33. An arm or cam I35 is also fixed on the shaft I25 and isadapted to actuate, at every half revolution of the shaft I25, interlockcontrol switch D.

A pair of links I4| are pivotally connected to the lower ends of thechannel members I I1 of the unloading mechanism 9, and these links I arefixed at their other ends to stud shafts I43 journaled in the fixedframe member 41. Likewise fixed on the stud shafts I43 are gears I45meshing with pinions I41 fixed on a second pair of stud shafts journaledin the fixed frame member 41. Fixed to these second stud shafts are apair of fingers I49 adapted, when raised in position, to receive andhold a carrier bar 9|.

Positioned immediately beneath the fingers I49 and supported at itsupper end by the fixed frame member 41 is a rollway I5I provided with aguide plate I53 and rollers I55.

The sequence control mechanism shown in Fig. 6 comprises an electricmotor |6| which-drives, through reduction gearing I63, a drum I65. Thedrum-I65 carries on its surface a plurality of contact members or stripsI61 extending for various distances about the periphery of thedrum,.each of which is adapted to engage, on rotation 01' the drum, oneof a plurality of fixed contacts I69. Y

' the drum I65 over that portion of one revolution of the drumrepresented by the heavy black lines.

In series with the switches closed or opened by the operation of thesequence control mechanism, as set' out above, are the several switchesshown diagrammatically in Fig. 8, which switches are actuated, as shownin the figure, by the several interlocking control switches A, B, C, D,and E. It is accordingly apparent that before any particular motor orother actuating mechanism can be energized, it is necessary that boththe sequence control mechanism in its operation shall have closed theswitches for that circuit and that the switches controlled by theinterlock control mechanism shall likewise be closed.

The timing device shown in Fig. '7 comprises a motor "I which drivesthrough reduction gearing I13 the shaft I15, slidable along the shaftI15, but keyed thereto, is a friction wheel I11, which is in frictionalengagement with the face of plate I19 secured to one end of shaft I8I.Disc I83 is mounted on shaft I8I and carries on its outer surface acontact member I85, which is adapted to engage, during a portion of therotation of disc I83, fixed contact I81. Contacts I85, I81 arepositioned in the circuit for the sequence control mechanism motor I5I,

and this motor consequently is energized onlywhen these contacts areclosed.

The friction wheel I11 is movable along the shaft I15 and may bemaintained in any desired position thereon by means of the guide memberI89 which is threaded on the screw shaft I8I. A pointer I93, attached toguide I88, indicates on scale I95 the position'of friction wheel I11along the shaft I15. Screw shaft I8I may be rotated by means of theknurled knob I81 affixed thereto.

In the treatment of metal sheets, for example, steel sheets, inaccordance with my invention, the sheets are first sheared approximatelyI longer than the final length, and at the same 7 time a plurality ofholes evenly spaced along the end of the sheet and of elongated form toallow for expansion are punched in this edge portion. Such a sheet isshownin Fig. 4, and is designated by the reference character 2!", theholes being indicated by the reference character 203. After the sheetshave been treated in accordance with my invention, the sheets aresheared along the line 205, and the extra length having the holespunched in it is thus removed.

The steel sheets 2III are carried through the apparatus supported oncarrier bar 8| (Fig. 5). The body portion of this carrier bar 9| is achannel section made of suitable material to withstand the temperaturesto which it is subjected, and designed to absorb the least amount ofheat possible. The web of the channel section will desirably be cored,cut or punched out, as shown at 209, in order to reduce the weightthereof. Hooks 201 are attached to the channel section, at properlyspaced intervals to correspond with the holes 203 in the sheet steel,either by welding or by being clamped by nuts threaded on the shanks ofthe hooks.

In order to visualize the operation of the apparatus in accordance withthis invention, let us assume that a sheet of steel 2IlI is being heatedin the furnace chamber 25 and that the various elements are in theposition shown in Fig. 1. It will be noted that there are a plurality ofsteel sheets I hanging in the pit below the furnace, supported from thecarriers 9| resting on the conveyor 3. Those sheets of steel to the leftof the furnace opening 21 have as yet not been heat treated, while thoseto the right of the furnace opening have been heat treated in thefurnace. It will be seen that the heat given off by the treated sheetsin the pit 26 is to a large extent absorbed by the untreated sheetswhich consequently receive a certain degree of preheating before beingplaced in the furnace chamber 25. The carrier II3 of the loadingmechanism 1 is in its lowermost position with a bar carrier 8| restingin the flanges H8. The hooks 201 of this particular bar carrier 9| arefirmly supported against the fixed bar 2 secured in the T-shaped supp ling members 43. A fresh sheet of steel 2III is then manually placed onthe hooks 281 of this bar carrier 8|.

In the meantime the motor I1I of the timing control mechanism has beenrunning, and consequently the shaft I8I and the disc I83 have beenrotating at a speed determined by the position of the friction wheel I11along the shaft I15. When the steel sheet 2I)I within the heatingchamber 25 has been in this chamber for the predetermined period of timefor which the timing control mechanism has been set by adjustment of thefriction wheel I11 by means of the knob I 91, the contacts I85 and I81are closed through the rotation of the disc I83. these contacts areclosed, the motor I 5| of the sequence control mechanism is started anddrum I55 begins to rotate. This point is indicated in Fig. 9 by thefirst arrow at the top of the figure. As the drum I65 rotates, thecircuit to the timer motor "I is broken, and the action of the timingdevice stops. At the same time the circuit to the chamber hoist motor 8|is closed and, the reversing switch and power switch controlling thismotor, as shown in Fig. 8. being in the proper position by reason of theaction of the interlock control contacts in the competion of the lastcycle of operation, the motor 8| is energized to rotate the drums H andlower the carrier81 bearing the sheet 2M undergoing treatment.

This lowering action continues until the carrier bar 8| is deposited onthe chains 3| of the conveyor 3 and until the carrier 81 has descendedan additional distance suflicient to disengage the flanges 88 thereoffrom the bar carrier 8|. At

trolling the operation of motor 59.

The power switch controlling the operation of motor 55 being closed, thefurther rotation of drum I 55 of the sequence control mechanism closesthe circuit leading to the conveyor motor 59 and energizes this motor.Crank disc 55 is thereby given one complete revolution, which motion istransferred to the ratchet wheel 48 by the action of arm 5|, andadvances this ratchet wheel one notch, thereby moving the conveyorchains 3I a suflicient distance to bring the bar carrier 9i, on which issuspended the sheet of steel 20I next to be treated, directly above theflanges 89 of the lowered carrier 81. In the meantime, the cam Blrotating with the crank disc 55 actuates the interlock control contactC. Actuation of this contact, as shown When in Fig. 8, results inclosingthe control circuits completing a half revolution, move cars IIII alongwhich (1) close the power switch in the circuit leading to motor- 8|,and (2) open the power switch in the circuit leading to motor 59, thusstopping further rotation oi the crank disc and further movement oi theconveyor 8.

The continued rotation of the drum I55 the sequence control mechanismagain closes the circuit leading to the chamber hoist motor 8|, and

the power switch in this circuit having been closed 7 through actuationof contact C, motor 8| is again energized, this time serving to raisethe carrier 81, which brings with it the bar carrier 9| and the sheet2III to be treated, into the furnace chamber 25. As the carrier 81reaches its uppermost position adjacent the top of the furnace chamber25, the second sleeve 93 on the cable or chain 82 actuates the interlockcontrol switch E, this time in an upward direction. Such aotu'ationoithe control switch E, as shown in Fig. 8, closes control circuits which(1) throw the power switch in the circuit to motor 8| 011, thus stoppingthe motor and the upward movement of the carrier 81, and (2) throw thereversing switch governing the operation of motor 8| from up to downposition.

' As this is done, continued rotation of the drum I65 of the sequencecontrol mechanism closes the circuit starting timer motor III which setsin operation the timing control mechanism that will serve to determinethe period of time that this sheet 2! will remain in the furnace chamber25. At the same time the sequence control mechanism closes switches inthe circuits to the two motors I which control the loading and unloadingmechanisms I and 9. The power switches for these motors controlled bythe interlock control mechanism being in closed position, and thereversing switch therefor being set in position for upward movement,these motors are energized to draw the carriers I I8 upwardly. Thisaction raises the fresh sheet of steel that had been manually placed onthe hooks 201 of the bar carrier 9| resting against the stop 2| I upbetween the channel members I I1 01 the loading mechanism and at thesame time raises the treated steel, sheet in the extreme right positionon the conveyor 3 up between the channel members III of the unloadingmechanism 9. As the two carriers 8 reach their uppermost position withinthe channel members II I, they actuate interlock control switches A andB, respectively. The actuation of control switch A, as shown in Fig. 8,throws the power switch in the circuit controlling the operation of thecorre-' sponding motor I 05 into off position, thus stopping the upwardmovement of the corresponding carrier II3. Similarly the actuation ofswitch B throws the power switch and the-circuit controlling theoperation of that motor I95 into off position. When both switches A andB have thus been actuated, the reversing switch'in the circuit to motorsI0! is thrown from up to down position, and the power switch in thecircuit leading to motor I38 is thrown into closed position.

Continued rotation of the drum I85 01 the sequence control mechanismcloses the circuit lead-' ing to motor I38, and the power switchcontrolled by the interlock control mechanism in this circuit havingalready been closed by the action of control switches A and B, thismotorI88 is energized. Crank discs I 28 are thereby rotated until theoperation of cam I35 actuates interlock control switch D, whichde-energizes motor I88 and stops the rotation of the crank discs I18.after they have the rails III3 by means oi? the connecting links I2I tothe position shown by the dotted lines in Fig. 1. The operation oiswitch D, as shown in Fig. 8, in addition to throwing the power switchin the circuit leading to motor I88 into oi! position, also throws thepower switches leading to'motors I05 and motor 8| into on, or closed,position.

Continued rotation of the drum I55 of the sequence control mechanismoperates to energize once more motors I05. This time, by reason of theactuation of the reverse switches through the interlock controlmechanism, in a direction to lower the carriers H3. The bar carrier 9Iand the steel sheet 20I carried by carrier I I3 01! the loadingmechanism I is thereby deposited at the extreme left end of conveyor 3,while the bar 9| and steel sheet 2III carried by the .unloadingmechanism 9 is deposited on the fingers I49, which have been raised intohorizontal position by the movement of channel members II'I into theposition shown by the dottedlines in Fig. 1. As the respective carriersII3 reach their lowermost position, they actuate interlock controlswitches A and B, which, as shown in Fig. 8, de-energize the motors I05,throw the reversing switch governing the operation of these motors fromdown to up position, and throw the power switch of the circuit leadingtomotor I 33 from oil to on position.

Continued further rotation of the drum I55 then again energizes motorI33 to cause the crank discs I23 to undergo a further half revolutionwith the resultant movement of cars IIII and the loading and unloadingmechanism carried back into the position shown in the solid lines inFig. 1. Therotation of crank discs I23 is stopped after one-halfrevolution by actuation of interlock control switch D, as-describedabove, and the conse quent de-energization of motor I88.

-The continued rotation of drum I65 then operates to open the circuitleading to motor IGI thus stopping further operation 'of the sequencecontrol mechanism. The timing control mechanism, however, continues torun until, after the sheet I has been in the heating chamber I for thepredetermined period'of time, the sequence control motor is startedthereby, and the entire sequence of operations justdescribed is.repeated.

As channel members III of the unloading mechanism 9 move back into theposition shown in the solid lines in Fig. 1, as just described, thefingers I49 are dropped from their horizontal position into the positionshown in the solid lines in Fig. 1, and' the bar carrier 9| and steelsheet '2III supported thereby are permitted to slide down the rollwayI5I.

It will be seen that in the operation just described-in detail abovethata sheet of steel is taken by the loading mechanism I, raised, broughtinto position over the end 01' conveyor 3, and lowered into position onthe conveyor, wh le at the same time, atthe right hand side of theconveyor a treated sheet has been raised from the conveyor, moved overabove the fingers I49, and then lowered and discharged from theapparatus along the rollway I5I. Meanwhile, the chamber hoist mechanismI5 has picked up a bar carrier 9| and steel sheet "I from the,

completed a halt revolution. Crank discs I23, in has then been movedforward so as to bring the 7 next sheet of steel under the opening 21.'Ultimately the sheet of steel placed by the loading mechanism at theextreme left end of conveyor 3 will be brought beneath the furnace,raised up and heat treated in the furnace, lowered back on the conveyor,moved to the extreme right hand position on conveyor 3, and dischargedfrom the apparatus by unloading mechanism 9.

It will be appreciated that, if desired, the unload'ng mechanism 9 mayplace the heat treated steel sheets directly on another chain conveyorsimilar to the conveyor 3, which will carry them to or through anysuitable after treatment, such as pickling, scrubbing, etc. It will alsobe appreciated that any desired pre-treatment may be given the steelsheets, and that the mechanism 1 may be designed to pick up from a chainconveyor the sheets of steel that have undergone such pre-treatment andplace them, as described, on the conveyor 3.

It will further be appreciated that, while an electrically heatedfurnace I has been described, that such furnace may, within the scope ofthis invention, be heated in any conventional manner, as by gas and thelike.

Many other modifications of my invention will be apparent to those sklled in the art, and it is accordingly to be understood that myinvention is not to be treated as limited to the particular details ofconstruction and operation set out above.

What I claim and desire to protect by Letters Patent is:

Apparatus for the treatment of metal sheets including in combination afurnace having a heating chamber open only at the bottom thereof andadapted to receive at least a single sheet of metal positionedvertically, a pit positioned beneath said furnace, a conveyor travelingbeneath said furnace and above said pit, means for moving said conveyorintermittently, a plurality of carrier bars adapted to rest transverselyon said conveyor and provided with means attachable to an edge of ametal sheet to be treated,

wherebya plurality of metal sheets may hang vertically in said pitsuspended from said carrier bars resting on said conveyor, a carriernormally positioned in said furnace chamber and adapted to engage any ofsaid carrier bars, means for lowering said carrier from said furnacechamber into proximity to said conveyor and for raising it into saidchamber again, whereby a carrier bar and attached metal sheet may beraised from said conveyor into the furnace chamber and replaced on saidconveyor again, hoisting means adapted to place a carrier bar andattached metal sheet on said conveyor adjacent one end thereof, andhoisting means adapted to remove a carrier bar and attached metal sheetfrom the conveyor at the opposite end thereof.

2. Apparatus for the treatment of metal sheets including in combinationa furnace having a heating chamber open only at the bottom thereof andadapted to receive at least a single sheet of metal positionedvertically, a pit positioned beneath said furnace, a conveyor travelingbeneath said furnace and above said pit, means for moving said conveyorintermittently, a plurality of carrier bars adapted to rest transverselyon said conveyor and provided with means attachable to an edge of ametal sheet to be treated, whereby a plurality of metal sheets may hangvertically in said pit suspended from said carrier bars restengage anyof said carrier bars, means for lowering said carrier from said furnacechamber into proximity to said conveyor and for raising it into saidchamber again, whereby a carrier'bar and attached metal sheet may beraised from sa d conveyor into he furnace chamber and replaced on saidconveyor again, hoisting means adapted to place a carrier bar andattached metal sheet on said conveyor adjacent one end thereof, andhoisting means adapted to remove a carrier bar and attached metal sheetfrom the conveyor at the opposite end thereof, at least one of said twolast named hoisting means comprising a track positioned above saidfurnace and extendng longitudinally of said conveyor, a car adapted torun on said track, hoist mechanism mounted on said car, a pair of spacedguide members attached to said car and extending vertically beneath thecar into proximity to saidjonveyor, a carrier adapted to engage any ofsaid carrier bars connected to said hoist mechanism and adapted to runbetween said guide members, and means for moving said car along saidtrack.

3. Apparatus as defined in claim 1 including in addition control meansadapted to effect automatically in predetermined sequence and atpredetermined intervals the operation of the mechanism described in saidclaim.

4. Apparatus as defined in claim 1 including in addition control meansadapted to effect automatically in predetermined sequence anckatpredetermined intervals the operation of the mechanism described in saidclaim and independent interlock control means adapted to preventpositively the effecting of an operation designed in normal sequence tosucceed a preceding operation until such preceding operation shall havebeen completed.

5. Apparatus for the treatment of metal sheets including in combinationa furnace having a heating chamber open only at the bottom thereof andadapted to receive at least a single sheet of metal positionedvertically, a conveyor traveling beneath said furnace, means for movingsaid conveyor intermittently, a plurality ofcarrier bars adapted to resttransversely on said conveyor and provided with means attachable to anedge of a metal sheet to be treated, whereby a plurality of metal sheetsmay hang vertically suspended from said carrier bars resting on saidconveyor, a carrier normally positioned in said furnace chamber andadapted to engage any of said carrier bars, means for lowering saidcarrier from said furnace chamber into proximity to said conveyor andfor raising it into said chamber again, whereby a carrier bar andattached metal sheet may be raised from said conveyor into the furnacechamber and replaced on said conveyor again, means adapted to place acarrier bar and attached metal sheet on said conveyor adjacent one endthereof, and means adapted to remove a carrier bar and attached metalsheet from the conveyor at the opposite end thereof.

6. Apparatus as defined in claim 5 including in addition control meansadapted to effect automatically in predetermined sequence and atpredetermined intervals the opcration of the mechanism described in saidclaim.

'7. Apparatus as defined in claim 5 including in addition control meansadapted to elfect automatically in predetermined sequence and atpredetermined intervals the operation of the mechanism described in saidclaim and independent interlock control means adapted to preventpositively the eiiecting of an operation designed in normal sequence tosucceed a preceding operation until such preceding operation shall havebeen completed.

8." Apparatus for the treatment of metal sheets including in combinationa furnace having a heating chamber open only at the bottom thereof andadapted to receiveat least a single sheet of metal positionedvertically, a conveyor traveling beneath said furnace, a plurality ofcarrier bars adapted to rest on said conveyor and provided with meansattachableto an edge of .a metal sheet to be treated, whereby aplurality of metal sheets may hang vertically suspended from saidcarrier bars resting on said conveyor, a carrier normally positioned insaid furnace chamber and adapted to engage any of said carrier bars,means (or lowering said carrier from said furnace chamber into proximityto saidfurnace chamber'and replaced on said conveyor.

again, means adapted to place a carrier bar and attached metal sheet onsaid conveyor adjacent one end thereof, and means adapted to remove acarrier bar and attached metal sheet from the conveyor at the oppositeend thereof.

9. Apparatus for the treatment of metal sheets including, ,incombination, a furnace having a heating chamber provided with a narrowopening at the bottom adapted to permit the passage of a single sheet 0!metal positioned verticaliy, a conveyor traveling beneath said furnace,a plurality of carrier bars adapted to rest on said conveyor, eachprovided with means attachable to an edge oi a metal sheet to be heatedand adapted to hold only a single sheet, whereby a plurality of metalsheets may hang vertically conveyor, means adapted to engage any one ofsaid carrier bars to raise it with its attached metal sheet from saidconveyor through said narrow opening into saidfurnace chamber and toreplace it in similar manner on said conveyor the conveyor at theopposite end thereof;

EDWARD r. HUFF.

